Using variables in Nginx location rules

Question

In Nginx, I'm trying to define a variable which allows me to configure a sub-folder for all my location blocks. I did this:

set $folder '/test';  location $folder/ {    [...] }  location $folder/something {    [...] } 

Unfortunately, this doesn't seem to work. While Nginx doesn't complain about the syntax, it returns a 404 when requesting /test/. If I write the folder in explicitly, it works. So how can I use variables in location blocks?

Answer 1

You can't. Nginx doesn't really support variables in config files, and its developers mock everyone who ask for this feature to be added:

"[Variables] are rather costly compared to plain static configuration. [A] macro expansion and "include" directives should be used [with] e.g. sed + make or any other common template mechanism." http://nginx.org/en/docs/faq/variables_in_config.html

You should either write or download a little tool that will allow you to generate config files from placeholder config files.

Update The code below still works, but I've wrapped it all up into a small PHP program/library called Configurator also on Packagist, which allows easy generation of nginx/php-fpm etc config files, from templates and various forms of config data.

e.g. my nginx source config file looks like this:

location  / {     try_files $uri /routing.php?$args;     fastcgi_pass   unix:%phpfpm.socket%/php-fpm-www.sock;     include       %mysite.root.directory%/conf/fastcgi.conf; } 

And then I have a config file with the variables defined:

phpfpm.socket=/var/run/php-fpm.socket mysite.root.directory=/home/mysite 

And then I generate the actual config file using that. It looks like you're a Python guy, so a PHP based example may not help you, but for anyone else who does use PHP:

<?php  require_once('path.php');  $filesToGenerate = array(     'conf/nginx.conf' => 'autogen/nginx.conf',     'conf/mysite.nginx.conf' => 'autogen/mysite.nginx.conf',     'conf/mysite.php-fpm.conf' => 'autogen/mysite.php-fpm.conf',     'conf/my.cnf' => 'autogen/my.cnf', );  $environment = 'amazonec2';  if ($argc >= 2){     $environmentRequired = $argv[1];      $allowedVars = array(         'amazonec2',         'macports',     );      if (in_array($environmentRequired, $allowedVars) == true){         $environment = $environmentRequired;     } } else{     echo "Defaulting to [".$environment."] environment"; }  $config = getConfigForEnvironment($environment);  foreach($filesToGenerate as $inputFilename => $outputFilename){     generateConfigFile(PATH_TO_ROOT.$inputFilename, PATH_TO_ROOT.$outputFilename, $config); }   function    getConfigForEnvironment($environment){     $config = parse_ini_file(PATH_TO_ROOT."conf/deployConfig.ini", TRUE);     $configWithMarkers = array();     foreach($config[$environment] as $key => $value){         $configWithMarkers['%'.$key.'%'] = $value;     }      return  $configWithMarkers; }   function    generateConfigFile($inputFilename, $outputFilename, $config){      $lines = file($inputFilename);      if($lines === FALSE){         echo "Failed to read [".$inputFilename."] for reading.";         exit(-1);     }      $fileHandle = fopen($outputFilename, "w");      if($fileHandle === FALSE){         echo "Failed to read [".$outputFilename."] for writing.";         exit(-1);     }      $search = array_keys($config);     $replace = array_values($config);      foreach($lines as $line){         $line = str_replace($search, $replace, $line);         fwrite($fileHandle, $line);     }      fclose($fileHandle); }  ?> 

And then deployConfig.ini looks something like:

[global]  ;global variables go here.  [amazonec2] nginx.log.directory = /var/log/nginx nginx.root.directory = /usr/share/nginx nginx.conf.directory = /etc/nginx nginx.run.directory  = /var/run nginx.user           = nginx  [macports] nginx.log.directory = /opt/local/var/log/nginx nginx.root.directory = /opt/local/share/nginx nginx.conf.directory = /opt/local/etc/nginx nginx.run.directory  = /opt/local/var/run nginx.user           = _www